AU4 - , , , VC4. :
- , 261 9 , 2349 , VC4;
- , (Administrative Unit Overhead, AUOH) 9 , .
AU4 4.11.
HI, 2 - ;
- ;
Y - 1001nn11;
U - 11111111.
HI 2; 4.12 , HI 2.
10 ; VC4 AU4. 10 0 1023.
AU4 2349 , , .
3 , . .
, 3 , , (SONET) (SDH).
, , 783 STS-1 ( SONET, 51,84 /).
, , 0 782; . , , 0.
0 , 783 2- .
4.13 - AU4
VC4 AU4 (New Data Flag, NDF).
4 , : "0110".
, , : "1001".
27. -. -.
/ . - - DXC.
( , ), , () ,
|
|
- , . SDH VC-n (., , . 2-3), .
- SDH
- : , . . - , ( ):
- / (in);
- / (out);
- / (trib).
, ( - in, out, trib) N x N( . 2-46). : VC-1 (1,5 2 /), VC-2 (6 /), VC-3 (34 45 /) VC-4 (140 /). , : in-out, out-in, in-trib, trib-in, trib-out, out-trib, trib-trib.
-
- 4x4 ( 2x2), . 10-25. , 4x4, 16 . ( ) (.. "" "" - , ) 1 3, , "" 1 ( 3) "" 3 ( 1 ) . -
, 13, " " (13 " "). , (.. ).
, . 10-25 , .. , i j, , , . , . , 2 2x2, , 1, - (2 n - 1). . 10-25 , ,
.
28. STM-1. . . .
STM-1 9 270 , 2430 . 8000 , 155,520 / 125 .
, STM-1:
|
|
- (MS), 5 - 9
- (RS), 1 - 3
- STM, 4 .
STM-N:
- 270 9 N,
- RSOH ( ) =3*9*N=27*N ,
- MSOH ( ) = 5*9*N=45*N ,
- PTR () =1*9*N =9*N ,
- ( ) = 261*9*N=2349*N ,
- = 270*9*N=2430*N .
29. STM-1. .
STM-N STM-1, :
- , STM STM .
STM-256 STM-1
STM-1*4=STM-4
STM-4*4=STM-16
STM-16*4=STM-64
STM-64*4=STM-256
- N STM-1.
STM-1*N=STM-N, N=256
STM-1*256=STM-256
30. SDH. .
SDH : - , - , - , - , - . .
1) , , , SDH. .
2) /, / . /.
3) , . - -.
4) ( ). .
5) () . .
6) SDH - , .
. () SDH . , .. , , .. .
31. . . .
, , , , . , , . , .